Yes you can, with appropriate resistor, according to Atmel. See attached.
I think I'd do that into an optoisolator, and use the open collector output to drive a pin on the arduino.
That application note is dangerous if you do not know what you are doing it requires the system to be isolated from the mains as it makes direct connection to it.
If you just want to detect the presence of mains voltage then use an opto isolator.